# PWM fan speed control **URL:** \ **Category:** Programming\ **Created:** [May 22, 2022, 9:44pm UTC](https://forum.arduino.cc/t/pwm-fan-speed-control/994661 "2022-05-22T21:44:53Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![EGUVEN](https://avatars.discourse-cdn.com/v4/letter/e/ac8455/32.png) [@EGUVEN](https://forum.arduino.cc/u/EGUVEN)\ **Post date:** [May 22, 2022, 9:44pm UTC](https://forum.arduino.cc/t/pwm-fan-speed-control/994661/1 "2022-05-22T21:44:53Z")
While i was searching code for control my fan's speed with PWM i found this code. It is working partically but not working properly but i couldn't find what is wrong. I want that when i push any button that predefined fan speed will continously will work with that speed. ```cpp #define PIN_MEMBRAN_RIGHT 13 #define PIN_MEMBRAN_UP 12 #define PIN_MEMBRAN_DOWN 11 #define PIN_MEMBRAN_SELECT 10 #define PIN_MEMBRAN_LEFT 9 #define PIN_MEMBRAN_START 8 uint8_t membran_pin_list[] = { PIN_MEMBRAN_UP, PIN_MEMBRAN_DOWN, PIN_MEMBRAN_RIGHT, PIN_MEMBRAN_LEFT, PIN_MEMBRAN_SELECT, PIN_MEMBRAN_START }; #define PIN_FAN 6 int PushButtonInput_1 = 13; // Push button - set PWM Fan speed %25 int PushButtonInput_2 = 12; // Push button - set PWM Fan speed %50 int PushButtonInput_3 = 11; // Push button - set PWM Fan speed %75 int PushButtonInput_4 = 9; // Push button - set PWM Fan speed %100 void setup() { pinMode(PIN_FAN, OUTPUT); digitalWrite(PIN_FAN, HIGH); pinMode(PushButtonInput_1,INPUT_PULLUP); pinMode(PushButtonInput_2,INPUT_PULLUP); pinMode(PushButtonInput_3,INPUT_PULLUP); pinMode(PushButtonInput_4,INPUT_PULLUP); } void loop() { //-----------------25%---------------------- if(digitalRead(PushButtonInput_1)==HIGH){ analogWrite(PIN_FAN, 64); //Serial.print(PushButtonInput_1); } //----------------50%--------------------- if(digitalRead(PushButtonInput_2)==HIGH){ analogWrite(PIN_FAN, 128); } //------------------75%----------------------- if(digitalRead(PushButtonInput_3)==HIGH) { analogWrite(PIN_FAN, 192); } //--------------------------------------------- //------------------100%----------------------- if(digitalRead(PushButtonInput_4)==HIGH){ analogWrite(PIN_FAN, 255); } //--------------------------------------------- } ``` ---
**Author:** ![ruilviana](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/ruilviana/32/722429_2.png) [@ruilviana](https://forum.arduino.cc/u/ruilviana)\ **Post date:** [May 22, 2022, 9:52pm UTC](https://forum.arduino.cc/t/pwm-fan-speed-control/994661/2 "2022-05-22T21:52:02Z")
> [@EGUVEN](#): > > `if(digitalRead(PushButtonInput_1)==HIGH){` Hi, from what I understand from your code, the buttons are connected between the pins (13,12,11 and 9) and the GND. Correct? If so, change all lines lines if(digitalRead(PushButtonInput\_X)==HIGH){ to if(digitalRead(PushButtonInput\_X)==LOW){ ---
**Author:** ![EGUVEN](https://avatars.discourse-cdn.com/v4/letter/e/ac8455/32.png) [@EGUVEN](https://forum.arduino.cc/u/EGUVEN)\ **Post date:** [May 22, 2022, 10:00pm UTC](https://forum.arduino.cc/t/pwm-fan-speed-control/994661/3 "2022-05-22T22:00:19Z")
> Hi, > from what I understand from your code, the buttons are connected between the pins (13,12,11 and 9) and the GND. Correct? Yes. My membran has 7 buttons but i just defined 4 of them to control speed. ---
**Author:** ![EGUVEN](https://avatars.discourse-cdn.com/v4/letter/e/ac8455/32.png) [@EGUVEN](https://forum.arduino.cc/u/EGUVEN)\ **Post date:** [May 22, 2022, 11:09pm UTC](https://forum.arduino.cc/t/pwm-fan-speed-control/994661/4 "2022-05-22T23:09:10Z")
When i changed the code like this i got the result that i want. ```cpp void loop() { //-----------------25%---------------------- if(digitalRead(PushButtonInput_1)==LOW){ analogWrite(PIN_FAN, 64); //Serial.print(PushButtonInput_1); } //----------------50%--------------------- if(digitalRead(PushButtonInput_2)==LOW){ analogWrite(PIN_FAN, 128); } //------------------75%----------------------- if(digitalRead(PushButtonInput_3)==LOW) { analogWrite(PIN_FAN, 192); } //--------------------------------------------- //------------------100%----------------------- if(digitalRead(PushButtonInput_4)==LOW){ analogWrite(PIN_FAN, 255); } //--------------------------------------------- } ``` I want to ask 1 more question. If i want to run my fan with %25 of it's power dividing 255/4=64 than, **analogWrite(PIN\_FAN, 64);** is this right ? ---
**Author:** ![ruilviana](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/ruilviana/32/722429_2.png) [@ruilviana](https://forum.arduino.cc/u/ruilviana)\ **Post date:** [May 22, 2022, 11:24pm UTC](https://forum.arduino.cc/t/pwm-fan-speed-control/994661/5 "2022-05-22T23:24:10Z")
Hi, theoretically yes; but applying 25% of the pulse time to HIGH on the fan will make it spin at 25% of its speed? ---
**Author:** ![EGUVEN](https://avatars.discourse-cdn.com/v4/letter/e/ac8455/32.png) [@EGUVEN](https://forum.arduino.cc/u/EGUVEN)\ **Post date:** [May 23, 2022, 7:20am UTC](https://forum.arduino.cc/t/pwm-fan-speed-control/994661/6 "2022-05-23T07:20:18Z")
It is spinning, it worked but i am sure, it is not the %25 of it's total power. It is still working loudly but more less than %100. I want that it works with it's minimum capacity. ---
**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\ **Post date:** [November 19, 2022, 7:21am UTC](https://forum.arduino.cc/t/pwm-fan-speed-control/994661/7 "2022-11-19T07:21:14Z")
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